(1) Field of the Invention
The present invention relates to cephalosporin derivatives and their non-toxic salts having excellent antibacterial activity and good oral absorptivity.
(2) Prior Art
Orally absorbable cephalosporin compounds having a 2-carboxymethoxyimino-2-(2-aminothiazol-4-yl)acetamido group at the 7-position of the cephem nucleus are known in U.S. Pat. No. 4,699,981. In addition, among cephalosporin drugs used clinically for oral administration are cephalexin, cefachlor, cefixime and the like. However, these oral cephalosporin drugs are much inferior to the cephalosporin drugs developed recently for injectional administration in terms of antibacterial activity and antibacterial spectrum against various pathogenic bacteria.
Under such circumstances, it is desired to discover new oral cephalosporin drugs having stronger antibacterial activity and wider antibacterial spectrum.